In a motor vehicle it is known practice to use a certain number of sensors to measure various parameters.
It is notably known practice to mount within each wheel of the vehicle an electronic measurement unit comprising one or several sensors enabling one or several parameters to be measured. Such an electronic measurement unit is generally mounted inside the tire, on the internal face of the tread, or alternatively on the inflating valve. This unit measures parameters and transmits them in full or in part to a computer of the vehicle so that it can determine a state of the wheel or of the vehicle.
By way of example, such an electronic measurement unit may make it possible to measure the acceleration of the wheel, the knocks experienced by the wheel or alternatively the tire pressure, so as respectively to determine the speed of the vehicle, the load thereon or a fault with the inflation of the wheel. In these applications, the central frequencies used are of the order of a few hertz, for example of 7.8 Hz when the vehicle is running at approximately 60 km/h.
There are certain functions specific to the electronic measurement unit that need to be able to be activated or not, or to have their operating parameters adapted according to the quality of the road. By way of example, for measuring vehicle load, it may be desirable to adapt the value of the parameters of a filter used for processing the measured signal, which processing is performed by the electronic measurement unit or to adapt the load thresholds, according to the characteristics of the road.
There is not at the present time any solution that makes it possible to determine the quality of the road so as to activate certain functions or adapt the operating parameters of an electronic measurement unit mounted in a wheel of a motor vehicle.